1. Field of the Invention
The invention relates to a pressurized reservoir closure device incorporating manual measurement means.
2. Summary of the Prior Art
Reservoirs for oil or other liquids, used in particular in aircraft propelled by jet engines, are subject during operation of the engine to a degree of pressurization.
The sealing at the filling opening is conventionally provided by a lockable cap, but only assuming that the locking is effective. It is therefore necessary to take precautions against the possibility of the omission to replace the cap or, alternatively, ineffective locking. In this eventuality, when the engine is started, or the supply circuit of the reservoir is operative, there will be an at least partial expulsion of fluid contained within the reservoir, which will have serious consequences for the longevity of the engine or for its environment. Various proposals have been put forward based on electro-mechanical or mechanical devices. Electro-mechanical devices indicating the positive closure of the reservoir are not always satisfactory or are too costly. A mechanical solution is proposed in No. FR-A-2 500 412 and consists of a device for closure of the reservoir under pressure. The device includes a cylindrical casing secured in the opening of the reservoir. The casing is closed by a cap traversed by a pin carrying at one end a locking plate which is brought by rotational action into locking engagement beneath an internal flange of the casing, the other end of the pin being provided with a lever which, in the position corresponding to the locking position, comes into engagement with a recess of the cap. The cap is attached by a conventional retention device to the casing so that it cannot be lost when it is not engaged in the opening of the casing. The bottom of the casing carries a rod of a piston which can be displaced into the lower part of the casing. The end of the rod is provided with a compression spring and a sealing member which is capable of being applied against the bottom of the casing and to close off passages traversing the casing and discharging above that part of the casing serving as the piston chamber. The spring, in its rest position, holds the sealing member spaced from the bottom of the casing in order to enable the passage of liquid for refilling purposes.
During start-up of the engine, a duct discharging into a chamber formed below the piston feeds liquid under pressure which displaces the piston against the action of the spring towards the opening of the casing and drives the seal member into tight contact with the bottom of the casing.
The device ensures substantial security in use, but unfortunately, it includes numerous mechanical parts which substantially reduce the section of the passage for the oil during refilling of the reservoir and moreover, renders the device costly to produce; furthermore, it requires use of a liquid under pressure possibly supplied through a duct connected to a pressure generator which is started up before or during use of the reservoir fluid.
The invention is concerned with the production of a closure for a pressurized reservoir comprising a limited number of parts, the device enabling, furthermore, the control of the fluid level contained within the reservoir and the withdrawal of a sample.